Sorry, I understood which one of the two I'd prefer as a middle name.
If I had to choose one for
Michelle:
Michelle RoseMichelle Leonor
And actually, I think I would leave the choice to my partner.
Nicole at least has a family significance for me. But it sounds so odd to me that I couldn't pick it now. But if my partner preferred it, I would go for it.
By the way, I used to kind of like
Nicole. No idea what happened but at the moment I can't stand the sound at all.